Air compressor



p s, 1936 v A. 2.5 m 2,053,593

AIR COMPRESSOR Filed Oct. 2, 1953 3 Sheets-Sheet 1 1/7 I INVENTORSATTORNEY Sept. 8, 1936.

A. ZISKA r AL AIR COMPRESSOR 1933 3 Sheets-Sheet 3 Filed OCt. 2

I lllllllllllllllllllll Patented Sept. 8, 1936 PATEEEN'T, OFFICE v AIRCOMPRESSOR Adam 'Ziska, Wauwatosa, and Conrad A. :Biebler,

Shorewood, Wis.

Application October 2, 1933, SeriaINo. 691,812 16-Claims. (o1. zen-58)contacts with the air either 'before, during, or

aitercompression, in which-means are'provided in which the constructionis'such that seli-lubrieating material forms 'oneof-therelatively-sliding surfacesorrelatively-movable parts of the aircompressor, so that the air is drawn in, compressed, and stored withoutcontact with 'any oil whatsoever.

' Incertain classes-of work, forexamplesupplying compressed air or othergas in dispensing beverages, such, for example, as been it is highlydesirable, though heretofore unaccomplished, to supply compressedair-absolutely free from any'oil or oil fumes or any smell of oil.Thisrequirement alsoexists in other 'types-ofcompressed-air work.Although this is-onlyone instance-of the need -of-compressed air freefrom oil fumes or oil, it is'obvious that there are numerous otherconditions under which it is required, such for 'instance, as dentalwork, spraying, and'soforth.

Further objects are to provide a 'unitarystructure in which a motor and'a compressor are formed as a unit and may be used "as such, if desired,but in which such composite unit formed of the motor and compressor"form, in effect, the relatively heavy base of the 'uriitary-structm'e,the upper portion of thestructure consistingof a storage tank mounteddirectly upon the compressor and surmounted by automatic control andindicating devices controlling the operation of the motor in accordancewith the air pressure, and

" alsocontrolling the pressure of the discharged'air by means of anautomatic pressure reduction valve, suitable gauges being provided andthe entire upper structure being covered by a closure cap mergingintothe outline-of'theta'nk.

Further objects are to provide a unitary construction in which therelatively heavy base formed of the electric motor and the compressorunit merge into the outline of the tank, such, for example, as acylindrical tan'k, so that the entire structure has no exposed runningparts, "but instead in which the unitary construction provides asubstantially cylindrical unit which is complete in itself and whichrequires no additional fittings whatsoever.

of wiring with the motor forming a portionjof the base of theapparatua'such'wiring being carried in permanently mounted rcondu'itsecured to the tank, and the *base and the'upper portion havinginterengaging'electrical connectors so that when the tank is removed,theconnection is automatically brokenwithouthaving 'anyloose wireswhatsoever, and when the tank is "replaced, the connection isaga'inmade, all without the need of disconnecting or reconnectinganywireswhat'soever;

Further objects are to provide a unitary air compressor constructioninwhich the motor and air compressor constitute arelatively heavy 'basefor the device, the lighter 'taiik structure being mounted thereonandfinithi's manner avoiding noise and vibration, theair'compres'soribeing also so constructed that a substantially perfectbalancing of the moving parts is obtained, thereby additionally avoidingvibration and noise. Further objects are to provide a unitary'aircompressor construction in which the air coni-' pressor unit ispreferably annular, though ob 0 viously it maytake other shapes, and isprovided with a plurality] of "radial cylinders and with a, floatingcentrally located crank shaitfor driving the pistons of the cylinders,such floating shaft being slidably coupled to the driving shaft of thelubricating materialjin'which the articulatedends o'fthe connecting rodsare also hushed with this material, and :in which a driving head issupportedflthrou'gh the medium ofb'a'll bearings from the crank so that anoilless construction results, the 'cornpressofbeing divided off from themotor by a transverse 'partitiorrformed preferably .in'tegrally with thecompressor" unit,su'ita ble ventilation for the motor being: provided byopenings in the lower andupperportion of the structure that forms thehousing for the motor, the upper por-' tion oi the air compressor unitconstituting an intake t'cha'mber, the unit itself bein'gpreferablyprovided with an annular intake chamber equipped with a removable ringof filtering mai- I ter'ral. I i V r l f Further objects are to providean air compressor'in' which removable valve guiding" means close theouter openingsthro'ug'h thebody portion 7 of the 'c'ompressor'inalignment with the 'radial'f cylinders and, inone' form'o'fthe'invention. in '55 which the valve itself directly seats upon the sleevelining the cylinder, the construction pro- 'viding an annular chambercircumscribing the cylinders and into which the cylinders discharge pastthe valves.

Further objects are to provide an air compressor which may be formed inany size, such, for example, as a small unit suitable for use intaverns, or in sand blasting, or in other work where a relatively smallcompressor is desired, although obviously as the description of theinvention proceeds, it will be apparent that the compressor can be madein any size desired.

Further objects are to provide an air compressor in which novel meansare used to secure the pins for the connecting rods to the driving headcarried by the crank in a manner to provide an extremely compact andsecure construction, and in which the construction lends itself to thelooking of one piston rod rigidly to the driving head carried by thecrank so that this piston rod forms a master rod for suitably holdingthe driving head, the other piston rods being articulated at each end.

Embodiments of the invention are shown in the accompanying drawings, inwhich:

Figure 1 is an elevation of the unitary air compressor, with partsbroken away.

Figure 2 is an enlarged vertical sectional view on the line 2-2 ofFigure 1, such view being broken away. i

Figure 3 is a plan view on the line 33 of Figure 2, with parts brokenaway.

Figure 4 is a view of the top of the apparatus with the cap removed.

' an air compressor unit or body portion 2, an

unit.

electric motor unit 3, a finishing support or base portion 4, and acover 5 surmounting the storage tank, the compressor and motor, togetherwith the finishing base portion 4, constituting,

in effect, the relatively heavy base of the apparatus. The aircompressor unit is joined to the tank by means of a short pipe 6provided with detachable fittings l and 8. It is also preferable toprovide a drain cock 9 for the air compressor Referring particularly toFigures 1, 2 and 3, it will. be seen that the air compressor unitcomprises a body portion 2, as' previously described, which is equippedwith a downwardly extending annular flange I0 seating upon the stator llof the motor, the motor stator in turn resting upon the finishing. baseor support 4. The motor armature I2 is carried by the driving shaft l3and a ball bearing or step bearing indicated generally at 4 is providedfor supporting the lower end of the motor shaft.

In purchasing the motor for this apparatus, it is obvious that the endplates are not needed as the finishing base and the compressor togethertake the place of the end plates of the motor.

The three parts may be locked together in any suitable way, as -by meansof the tie bolts |5, such bolts being threaded into lugs I6 carried bythe compressor unit and being provided with nuts I! at their lower ends.

Referring in greaterv detail to the air compressor unit, it will be seenthat the body portion is provided with a plurality of radial cylindersl8. Each of these cvlinders is equipped with a piston l9. The pistonsare driven from a crank 20 which is counterweighted as indicated andwhich is carried by a floating crank shaft 2|. This crank shaft iscarried by a ball bearing indicated generally at 22 in Figure 2, and hasa sliding keyed fit with the upper end of the motor shaft. It is to benoted that the inner race of the ball bearing 22 is locked to the shaft2| and that the outer race is locked by means of a plate 23 to thetransverse partition wall 24 of the compressor structure. Thus thisbearing is a floating or semifloating bearing and is so made that theshaft may be directly slipped over the driving shaft of the motor inassembling or disassembling the parts.

The crank 20, of course, may be replaced by an eccentric if desired, andit is to be understood that the term crank hereinafter used is intendedto be interpreted in its broadest aspect.

Thiscrank 20 is provided with a shouldered portion 25 upon which theinner race of the lower ball bearing 26 rests. It is provided with athreaded reduced upper portion 21 which receives the nut 28 and washer29 which holds the inner race of the upper bearing 30 in place. Thedriving head 3| is provided with an intermediate small flange whichspaces the outer races apart and thus the driving head 3| is lockedagainst displacement either in an up or down direction and yet issupported by ball bearings from the crank.

The driving head 3| is provided with upper and lower flanges 32 and 33between which the ends of the connecting rods 34 are received. All ofthese connecting rods are articulated at both ends at the points wherethey are connected to the driving head and the cylinders, except one.This connecting rod is shown in Figure 2. It is provided with anenlarged inner head 35 which is curved to fit the outer face of thedriving head 3|. All of the connecting rods are secured by means of pins36. The connecting rod just described is immovable with reference to thedriving head 3| and constitutes, therefore, a master rod. From Figure 3it is apparent that it is held against motion with reference to thedriving head by means of the enlarged portion 35, as the enlargedportion 35 has an arcuate face which fits closely around the head andprevents rocking of the connecting rod 34 with reference to the head.This provides a very simple mode of locking the master rod to the headso that one rod does not rock with reference to the head.

Each of the pins 36 is provided with a grove which may be seen in Figure2 and which is shown in dotted lines in Figure 3 and is indicated by thereference character 31. The upper flange 32 of the driving head isprovided with an annular groove 38 in alignment with the grooves 37 ofthe pins. Cotter pins or split pins 39 are employed for locking thecrank pins in place. These split pins are merely slipped into the roundspace formed jointly by the groove 38 in the driving head and thegrooves 31 in the connecting rod pins, and consequently locks the pinsin place, as shown most clearly in Figure 3. The inner ends of theconnecting rods are joined by means of the pins 40 to the pistons l9. Itis preferable to bush each end of the connecting rods with aself-lubricating bushing, as indicated at 4| in Figure 3. Obviously itis not necessary to bush the inner end of the master rod previouslydescribed.

The body portion is bored out radially for the cylinders and either thepistons or liners for the aouamaa cylinders are @fonmed :o :aself-lubricatin imateniatsuch as,an alloy, qtgraphiteandimetal,sthoughobviously the invention is not to be limited to this. specific material,as any other :se1t-..luhrioat ingmaterial, having long wearmayabeused.

in the form of .the invention shown liners'liz (itself-lubricatingmaterial-:are provided for each cylinder. These liners are forced intothe cylinders .from the outer .side -inwardly until they strike smallflanges -,43 carried at ':the ,-inner ends of the cylinders. The pistonsare ,preferabiy provided .with piston rings .as indicated and may bemade of :any suitable materiel, such as least iron. These ,pistonsslide.freely within the :selflubricating sleeves and thus useof oil either(811 the pistons or at the crank or :at any of the joints, of :theconnectingrods is wholly avoided.

.In-the preferred :form of the invention, a disk valve 44 is providedand is pressed inwardlyrhy meanscf a spring-.45. This valve ;is providedwith a :guiding stem 46 integral therewithaand uided withina recessformed-in the valve plate-or valve guiding means 47. One of these platesis provided tor-each valve, as is obvious .frcm.-Fig ures thisself-lubricating material. 7

I he body portion is provided with an annular discharge chamber 48 whichcircumscribes =the cylinders and which opens into an enlarged portion:49. communicating with the tank by means of the pipe .6 :as shown inFigure 2. Thus :acommon annular discharge passageway is provided in thebody portion of the -compr.essor itself into whicheach radially'disposed ic linder dischar es.

The inlet for each of the cylinders is provided by means of one or moreapertures 5.0 which-are drilled downwardly through the -.cylinder wall,as shown in Figures 2 and 3. These apertures communicate with an annularintake passageway 51 and if desired, :the,annularpassageway 15.1 mayopen into the small segmental passages or spaces 52 between thecylinders. The annular passageway5-l is provided with a removableannular filtering pad or member 53 preferably supponted by a .gauzescreen '54.

The inlet chamber of the -a.i r -;.compress or ;is thus completelyseparated ofi from the motor by means of the transverse wall 24. Thisinlet .por-

tion'receives 13111 from the outside through aperthrough the relativelylarge extensive area of the annular intake passagers'l with "thecylinders. The filtering pad or member '53thus presents a very extensivesurface to the air entering the Qylinclers, although the actualapertures leading to the cylinders may be relatively much smaller asindicated. Thus there is no material .restric- I tion ,to the :free .airflow to the cylinders.

V The bottom portion of the :tank fits over the should part 56 of the.cQmPIBSSOr unit and lobkedthereto'ibyzmeans:ofsscrewsfifi.seerfieurez,so zthat the=tank :is rfreelyiremovable.

to be understood. that other iforms of valves may ibe :used. forexample, .as shown "in Figure 5., the valve ca-p. 59 :maybe:providedwith a hall waive 6D pressed'inwardly by means :of :a spring151 acarried rby azremovable ccaplike member 62. .I'his-.valve "mayseatland plose an aperture '63 leading intowthe:cylindenand.dischargeapertures 6.4 may be :provided as shovm in FigureIt is preferable, in the zeventsthis'ztyne iof. valve-is :used, toprovide 3a small gasket 265 for each valve cap. titheuppermortioneofithe tank carrieszapressure responsive automatic switchindicated generally atiGB in E'Eigure i4 and connected to the motortm'ough; the medium Of the cable .61. This cable extends :outwardlyia-hovethe .top 168 vofxthe tank Tl. through an aperture in the sidewalland is covered :by 'ana ornamental qmeta'l :conduit 69 rigidlyseonred.toitheztank, see "Figures land 4. This conduit mxtendsdownwardly and. carries a plug or other :member :fits a complementarymember 51;! supported from .an enlargement .12 formedronthe ornamentalbottom (or-base .por-

tion i4. Thus :when the tank :isremoved, it is obvious that :no thought:need be given the wiring as the tank and the :rigidiy :attached member10' may he :lifted directly from the compressor. and may be .replaced,athus .reestablishing the motor circuit.

The top of the tank alsozcarries a reducing'valve l3,isee Figured,controlled by a :knob 14 projecting through-the can. It is :alsopreferable to provide Pfihfl :automatic pressure responsive :switch 66with a manual cut-off :15 which .proj ects through the atop of :thecover'li, as-showrn in .Figlure ,1. Also it preferable :to provide agauge '16 for indicating the pressure within the :tank and a;gauge I1communicating :with :the discharge pipe 1-8 so :that thereduced pressuremaya-lso be read. V

311; will abezseen zpartioularlyirom Figure 1 that the tank mergesuniformly into the cap '5 at :the upper endiand at the lower end thecompressor and motor unit and supporting base form, ineffect, acontinuationof the :tank so that there are no exposed aoperatingparts-on the one :hand, and, on the, other hand, so that a very compact andornamental structure results.

It is to be particularlynoted that the tankmay be most easi y removed.-f-rom ,the rest of the apparatus by merely loosening one of thefittings, for instance the fitting :8, see .Figure 1, and :removingthescrews 58, see Figure 2, which hold the tank to the compressor unit.Thereafter the tank may be lifted directly-tram the base portion of thedevice.

However, the apparatus isso made that no attention whatsoever isrequired .iora great length of time. All of the .parts of the compressorare oilless and require no attention whatsoever. Also the motor .issupported by ball bearings and if desired, these hearings may be packedwith grease, though obviously this is not necessarily required. Thelower bearing I4, see Figure 2, which supports the weight .of the motor,.is easily accessible :by merely removing the cap 19.and this.

hearing may be suitably lubricated.

.It is to be noted particularly .from reference to Figures 2 and 3, thatthe incoming air entering through the apertures .55 is filtered by thefiltering pad 53 and passes :into the cylinders through the apertures50. It leaves the cylinders and enters the annular aperture 48,-thereafter passing into the tank, preferably a check-valve indicatedl-l ally at :80 .infi we 2 being provided, Pardoes not come in contactwith theoil or with any oil surface or bearing at any part in itspassage either into or outof the air compressor. This feature is ofparticular importance, as has been explained in detail hereinbefore.Obviously this principle could be used with any number of cylinders,oneor more as desired. Preferably, however, the cylinders are multiple, asshown in Figure 3, and are so arranged as to assist in the accuratebalancing of the device.

The incoming air enters the respective cylinders when the pistons havebeen drawn to their inner position, as shown in Figure 2, as the portsor entrance apertures 50 are then uncovered. Thereafter on thecompression stroke, the piston covers these openings and the airisdischarged past the valve 44. 1

It is to be noted also that the heavy parts of the apparatus constitutethe base, that is to'say,

. the motor and the compressor unit. These heavy parts tend tostabilize'th'e apparatus and the relatively lighter tank structure issupported therefrom. Obviously, vibration is not reinforced by the tankas would have been the case had the compressor and motor been supportedby the tank. In actual practice this device has been found very quiet inoperation and although of small size, it nevertheless is highlyefiicient and can deliver any required volume of air depending on theproportions of the device.

- It .is a portable apparatus, although if in stalled in taverns orsimilar places, it would be bolted down to its support, such, forexample, as the bar, as the device itself is ornamental in appearance.It will be seen further that the apparatus is simple to manufacture andreadily lends itself to quantity production.

Although this invention has been described in considerable detail, it isto be understood that such description'is intended as illustrativerather thanlimiting, as the invention may be variously embodied and isto be interpreted as claimed.

We claim:

1. An air compressor comprising anelectric motor having avertical'shaft, an air compressor supported fromand driven by saidmotor, a storage tank supported from and fed by said compressor, saidmotor, compressor and tank forming a unitary structure, pressureresponsive automatic control means carried by said tank and controllingsaid motor, said motor and compressor being detachable from said tankand constituting a base structure, and interengaging detachableelectrical connecting means carried by said tank and base structure andrespectively connected to said control means and to said motor.

'2. An air compressor comprising a unitary structure having an airstorage tank, an air compressor including a rotary shaft, a body portionsurrounding said shaft, a. plurality of radially arranged cylinders insaid body portion, pistons within said cylinders driven from said shaft,said body portion being located below said tank, and an electric motormounted below said compressor and operatively coupled to said shaft, theaxes of,

said shaft, a plurality of radially arranged cylinders in said bodyportion,pistons within said' cylinders driven from said shaft,'saidbody'portion ticular emphasis is laid on the fact that the'air' beinglocated below said tank, and a motor mounted below said compressor andoperatively coupled to said shaft, the axes of said tank, said bodyportion and said motor being in alignment, said tank, said body portionand said motor having external surfaces which approximately align toform a vertical, approximately cylindrical structure.

4. An air compressor comprising a unitary structure including anelectric motor, an air compressor supported by said motor and driven bysaid motor and having a suction compartment, at least one of eachrelatively movable portion of said air compressor being formed of amaterial that does not require oiling, a transverse division wallseparating said air compressor from said motor and constituting one wallof said suction compartment, and a storage tank supported from said aircompressor, the inlet to said suction compartment being located abovesaid compressor.

5. An air compressor comprising a storage tank, an air compressorsupporting said tank, an electric motor supporting said air compressorand operativelycoupled thereto, a pressure responsive electrical meanscarried on top of said tank and controlling said motor, and a cover forsaid electrical means, said cover, tank, compressor, and motor forming asubstantially cylindrical, vertical unitary structure and providing asubstantially continuous vertical, cylindrical side wall for the entirestructure.

6. An air compressor comprising a body portion having a plurality ofradial cylinders, pistons in said cylinders, and a centrally arrangedcrank for reciprocating said pistons, said body portion having anannular inlet portion provided with a ring of filtering material andhaving apertures extending from the annular portion into said cylindersand uncovered by the respective pistons when said pistons are at oneextreme limit of their stroke.

7. An air compressor comprising a body portion of approximately annularcontour and having a plurality of radially arranged cylinders, said bodyportion having an annular outlet passageway surrounding said cylinders,valves for said cylinders opening into said annular passageway, saidbody portion having a second annular passageway constituting an inletportion for said cylinders and having a plurality of aperturescommunicating with said last mentioned passageway and with therespective cylinders, said apertures being uncovered by the respectivepistons when said pistons are at the inner limit of their strokes, and acentrally arranged crank for reciprocating said pistons.

8. An air compressor comprising a body portion of approximately annularcontour and having a plurality of radially arranged cylinders, said bodyportion having an annular outlet passageway surrounding said cylinders,valves for said cylinders opening into said annular passageway, saidbody portion having a second annular passageway constituting an inletportion for said cylinders and having a plurality of aperturescommunicating with said last mentioned passageway and with therespective cylinders, said apertures being uncovered by the respectivepistons when said pistons are at the inner limit of their strokes, acentrally arranged crank for reciprocating said pistons, and an annularfiltering pad carried within said last mentioned annular passageway.

9. An oil-free air compressor comprising a body portion-having aplurality of radially arranged cylinders, each cylinder having a linerof self-lubricating material, a piston positioned within each cylinder,a centrally arranged crank, means connecting said crank with saidpistons, said means having articulated portions, said articulatedportions being lined with a self-lubricating material, and a valve foreach cylinder, said valves, in their open positions, being out ofcontact with said liners. V

10. An air compressor comprising a body portion having a plurality ofradially arranged cylinders, pistons mounted within said cylinders, acentrally arranged crank, an antifriction head mounted upon said crankand having annular spaced flanges, a piston rod constituting a distinctand separate unit from said head and rigidly locked to said head, and aplurality of piston rods connected to the remaining pistons andpivotally mounted between said overhanging flanges.

11. An air compressor comprising a body portion having a plurality ofradially arranged cylinders, pistons mounted within said cylinders, acentrally arranged crank, an antifriction head mounted upon said crankand having annular spaced flanges, a piston rod constituting a distinctand separate unit from said head and rigidly locked to said head, and aplurality of piston rods connected to the remaining pistons andpivotally mounted between said overhanging flanges, the articulated endsof said piston rods being lined with a self-lubricating material.

12. An air compressor comprising an electric motor having a projectingdriving shaft, an air compressor comprising a body portion supporteddirectly by said motor and having a floating shaft slidably andoperatively coupled to the free end of said driving shaft, said shafthaving an overhanging crank thereon, a driving head mounted upon saidcrank, said body portion having a plurality of radially arrangedcylinders, pistons mounted within said cylinders, piston rods connectingsaid driving head with said pistons, one of said rods constituting amaster piston rod and being rigidly coupled to said driving head, theremainder of said piston rods being articulated with said head and theirrespective pistons, the articulatedend of said piston rods beingprovided withliners formed of self-lubricating material, and pinspassing through said liners and joining said head and the pistons tosaid piston rods.

13. An air compressor comprising a unitary structure including an aircompressor unit having an annular body portion, an electric motor havingan annular field structure directly bolted to said body portion and inaxial alignment therewith, said electric motor having an armature and adriving shaft, said air compressor having a floating shaft coupled tosaid driving shaft and having an overhanging. crank, said body portionhaving a plurality of radially arranged cylinders, pistons within saidcylinders operatively coupled to said crank, said body portion havingopenings'extending outwardly and in alignment with said cylinders,valves located at each opening, and a valve guiding means closing eachof said openings, said body portion having an annular passagewaycircumscribing said cylinders and into which said valves open.

14. An annular compressor unit comprising a ring-like body portion, ashaft centrally arranged and carried in a floating manner by said bodyportion and having an overhanging crank, a driving head carried by saidcrank, said body portion having a plurality'of cylinders provided withliners and having openings in alignment with said cylinders closed bycaps, valves guided by said caps and controlling the discharge of thesaid cylinders, pistons mounted within the cylinders and operativelycoupled to the said driving head, said body portion having an annularpassageway surrounding said cylinders and into which said valves open,said body portion having an annular inlet passageway provided withopenings communicating with said cylinders and uncovered by said pistonswhen said pistons are at the inner end of their strokes, and filteringmaterial carried within said annular inlet passageway.

15. An air compressor comprising a body portion having a plurality ofcylinders, a shaft pivotally mounted within said body portion and havinga crank, a head carried by said crank, said head having a groove formedtherein, pistons Within said cylinders, connecting rods joining saidpistons and said head, at least one of said connecting rods having apivot pin operatively connecting such rod and said head,

said pivot pin havinga notch formed therein registering with'the grooveformed in said head, and a locking pin carried jointly by said grooveand said notch for locking said pivot pin to said head.

16. An air compressor comprising an electric motor having a verticalshaft, an air compressor unit supported and driven by said motor, and

7 an air storage tank supported and fed by said compressor, said motor,compressor, and tank forming a unitary structure and each beingsubstantially symmetrical about a vertical axis, said tank beingcomplete in itself and having a closed bottom, said air compressor unitbeing a complete unit independent of said tank.

ADAM ZISKA. CONRAD A. BIEBLER.

